ABD Cutaneous Oncology 3 — Questions and Answers
Question 1: Merkel cell carcinoma is most strongly associated with which infectious agent?
- Human papillomavirus 16
- Merkel cell polyomavirus (Correct answer)
- Epstein-Barr virus
- Human herpesvirus 8
Correct answer: Merkel cell polyomavirus
Merkel cell polyomavirus integration drives the majority of Merkel cell carcinomas.
Question 2: Which immunostain shows a characteristic paranuclear dot pattern in Merkel cell carcinoma?
- CK20 (Correct answer)
- TTF-1
- S100
- CD45
Correct answer: CK20
CK20 typically shows perinuclear dot-like staining while TTF-1 is negative, helping distinguish MCC from metastatic small cell lung cancer.
Question 3: The first-line systemic therapy class for advanced Merkel cell carcinoma is:
- BRAF inhibitors
- PD-1/PD-L1 checkpoint inhibitors (Correct answer)
- Hedgehog inhibitors
- Anthracycline chemotherapy
Correct answer: PD-1/PD-L1 checkpoint inhibitors
Avelumab and pembrolizumab (PD-1/PD-L1 blockade) are first-line for advanced MCC.
Question 4: Extramammary Paget disease of the vulva most often stains positively for which marker?
- CK7 (Correct answer)
- S100
- HMB-45
- CD20
Correct answer: CK7
The intraepidermal adenocarcinoma cells of EMPD are characteristically CK7 positive.
Question 5: Which finding on a mycosis fungoides biopsy is most specific for the diagnosis?
- Spongiosis
- Pautrier microabscesses (Correct answer)
- Munro microabscesses
- Civatte bodies
Correct answer: Pautrier microabscesses
Pautrier microabscesses—intraepidermal collections of atypical lymphocytes—are highly specific for mycosis fungoides.
Question 6: Sézary syndrome is defined by mycosis fungoides plus which additional feature?
- Nodal involvement only
- Erythroderma with circulating atypical T-cells (Correct answer)
- Large-cell transformation
- Bone marrow blasts
Correct answer: Erythroderma with circulating atypical T-cells
Sézary syndrome is the leukemic variant of CTCL with erythroderma and clonal Sézary cells in blood.
Question 7: Atypical fibroxanthoma classically arises in which clinical setting?
- Young immunosuppressed patients on the trunk
- Sun-damaged head and neck of elderly patients (Correct answer)
- Genital skin of middle-aged women
- Palms and soles of manual laborers
Correct answer: Sun-damaged head and neck of elderly patients
AFX typically presents as a rapidly growing nodule on chronically sun-damaged skin of the head and neck in the elderly.
ABD Cutaneous Oncology 3
Merkel cell carcinoma is most strongly associated with which infectious agent?